We are studying the microstructure of three dimensional biomimetic matrixes for their potential and/or improvement as vascular biomaterials. Surface textured Biomaterials have been examined to improve cell adhesion and tissue integration, however their topographies are unlike in viva cell adhesion substrates in both size range and structural complexity. In viva, many cells are adherent to an ECM, which have a complex 3-D topography in the macromolecular size range as small as 10 nm. Multiple studies indicate that simple Euclidian-like topographies in the micron range can influence cell function and differentiation. We are examining the effect of biological matrix textures by fabricating Biomaterials which precisely replicate the 3-D structure of ECMs well into the submicron range. We are using the high resolution SEM at the IMR to observe these structures. This pennits examining the effects of biological topography, separated as much as possible from biological chemistry, in the differentiation of adherent cells. The present studies are applied to vascular prosthetic applications, and hence examine this with respect to the ECM underlying arterial and venous vascular endothelium.